San Rafael Swell -- MK Tunnels -- Inside of Tunnel

Local men were employed in this top secret project known as the Government Tunnels until recently--now referred to as MK Tunnels. The interior of the tunnels was painted white and state of the art instruments were placed within the shafts to document the effects of explosions. Remnants of the wiring to the instruments can still be seen in some of the tunnels. They could tell what pieces of walls gave way by the white paint. In 1948 the Federal Government sent some military officials to the San Rafael Swell to build a series of tunnels over a 300 acre area. Morrison Knudsen Corporation (MK) won the construction contract to blast the tunnels in the solid rock. It was a top secret mission; not even local employees were infomed about the reason behind the work they were doing. Over a period of four years, blasting was done to create tunnels in three different areas. Once the tunnels were made, varying amounts of TNT were set off on top of the rock structure. Most supposed it was to test the sandstone to see if it could withstand a nuclear blast. This tunnel is the largest of the tunnels.

Click tabs to swap between content that is broken into logical sections.

Local men were employed in this top secret project known as the Government Tunnels until recently--now referred to as MK Tunnels. The interior of the tunnels was painted white and state of the art instruments were placed within the shafts to document the effects of explosions. Remnants of the wiring to the instruments can still be seen in some of the tunnels. They could tell what pieces of walls gave way by the white paint. In 1948 the Federal Government sent some military officials to the San Rafael Swell to build a series of tunnels over a 300 acre area. Morrison Knudsen Corporation (MK) won the construction contract to blast the tunnels in the solid rock. It was a top secret mission; not even local employees were infomed about the reason behind the work they were doing. Over a period of four years, blasting was done to create tunnels in three different areas. Once the tunnels were made, varying amounts of TNT were set off on top of the rock structure. Most supposed it was to test the sandstone to see if it could withstand a nuclear blast. This tunnel is the largest of the tunnels.